The rise of tick-borne diseases, particularly anaplasmosis, is a growing concern in Canada, as highlighted in a recent report by the Canadian Medical Association Journal (CMAJ). This bacterial illness, transmitted by blacklegged ticks, is gaining traction and posing a significant public health threat.
In this article, we delve into the story of Martin Haché, an 80-year-old retiree, who unexpectedly fell ill due to anaplasmosis. His case, documented in the CMAJ report, serves as a stark reminder of the expanding reach of tick-borne diseases across the country.
The Growing Threat of Anaplasmosis
Anaplasmosis, though less familiar than Lyme disease, is rapidly increasing in prevalence. While Lyme disease infected over 7,100 Canadians last year, anaplasmosis case counts have surged since becoming nationally notifiable in 2024. Most cases are concentrated in Ontario and Nova Scotia, with Nova Scotia bearing the brunt of tick-borne illnesses.
Dr. Michael Quon, an internist at The Ottawa Hospital who treated Mr. Haché, emphasizes the significance of this trend. He notes that healthcare practitioners are now regularly encountering patients with anaplasmosis and other tick-related illnesses, a stark contrast to just a few years ago.
Symptoms and Severity
Anaplasmosis often presents with mild or even asymptomatic symptoms, making it challenging to diagnose. Unlike Lyme disease, which typically causes a distinctive bullseye rash, anaplasmosis exhibits non-specific symptoms such as fever, fatigue, chills, headache, and nausea. However, if left untreated, the disease can progress to severe complications, especially in older or immunocompromised individuals.
In Ontario, 21% of reported anaplasmosis cases between 2023 and 2025 required hospitalization, and four patients died. In comparison, the hospitalization rate for Lyme disease over the same period was significantly lower, at 3.8%, with no reported deaths.
Rare Complications
One of the most concerning aspects of anaplasmosis is the potential for rare and severe complications. Mr. Haché, for instance, developed myocarditis, an inflammation of the heart muscle, which is exceptionally rare with anaplasmosis. Dr. Quon and his colleagues believe Mr. Haché's acute myocarditis was caused by anaplasmosis, a finding that underscores the need for further understanding of this disease.
The Spread of Blacklegged Ticks
The rise of anaplasmosis is closely linked to the spread of blacklegged ticks across Canada. Warming temperatures have fueled the expansion of these ticks, particularly in the eastern provinces of Ontario, Quebec, Nova Scotia, and New Brunswick. This expansion has also led to an increase in Lyme disease cases.
Veterinarians in eastern Ontario have reported a rise in anaplasmosis cases in dogs, indicating the growing presence of this disease. Dr. Katie Clow, an assistant professor at the Ontario Veterinary College, studies vector-borne diseases and notes the shocking changes in tick populations and their ability to transmit multiple pathogens.
Hotspots and Personal Experiences
Southeast Public Health, encompassing Kingston and surrounding areas, has the highest infection rates for both Lyme disease and anaplasmosis in Ontario. Nova Scotia, however, remains the hardest-hit province, with 69% of anaplasmosis cases in 2024. Residents like Katie Crowell and Greg Welsh have experienced multiple infections, highlighting the severity of the situation.
Prevention and Future Outlook
The good news is that antibiotics are highly effective against anaplasmosis. Additionally, the precautions taken to prevent Lyme disease, such as covering ankles and legs, using tick repellents, and regular tick checks, will also help prevent anaplasmosis, as both diseases are spread by the same tick species.
Public health researchers are now focused on understanding whether anaplasmosis will follow a similar growth trajectory as Lyme disease. In the meantime, individuals like Mr. Welsh and Mr. Haché are adapting their daily routines to minimize their risk of tick bites.
As we enter the summer months, it's crucial to raise awareness about ticks and the diseases they carry. By taking simple precautions and staying informed, we can protect ourselves and our communities from the growing threat of tick-borne illnesses.
